1. Technical Field
The technical field to a drive apparatus, and more particularly relates to a drive apparatus equipped with a drive generator for generating drive.
2. Description of the Related Art
Example of conventional vibration actuators for generating vibration are given in Japanese Laid-Open Patent Applications JPH11-271480 and JP2000-32785, in which electrodes are provided at four places on a piezoelectric element, AC voltages of different phase are applied to two pairs of diagonally opposite electrodes, and longitudinal vibration and curved vibration are generated harmonically in the piezoelectric element, which yields a drive force. Also, there are known drive apparatus in which such vibration actuators are used.
In general, a vibrator has to be subjected to suitable pressurization to obtain a drive force. As shown in FIG. 20, in JPH11-271480, two rails 201a are provided to a support base 201, and grooves 202b provided to a first moving body 202 are disposed over the rails 201a. A second moving body 203 in which grooves 203a are formed are disposed over two rails 202a provided to the first moving body 202. A vibration actuator 204 having a protrusion 204a is fixed to the support base 201, and is pressurized with respect to the first moving body 202 by a biasing member 204b fixed to the support base 201. When drive voltage is applied to the vibration actuator 204, the vibration actuator 204 undergoes curved vibration, and the first moving body 202 moves along the rails 201a. Also, a vibration actuator 205 having a protrusion 205a is fixed to the first moving body 202, and is pressurized with respect to the second moving body 203 by a biasing member 205b fixed to the first moving body 202. When drive voltage is applied to the vibration actuator 205, the vibration actuator 205 undergoes curved vibration, and the second moving body 203 moves along the rails 202a. 
Meanwhile, as digital cameras have increased in image quality and decreased in size in recent years, a digital camera has been known that comprises a drive apparatus for driving a correction lens (image blur correction apparatus) in order to eliminate image blur from captured images (see Japanese Laid-Open Patent Application JP2004-126028, for example). This image blur correction apparatus will be described through reference to FIG. 21.
An image blur correcting lens group L3 for correcting image blur during image capture is fixed to a pitch movement frame 332 that is capable of moving in the pitch direction, which is a first direction (Y direction), and in the yaw direction, which is a second direction (X direction). This pitch movement frame 332 has a bearing 332a on the X direction negative side, and a rotation stop 332b on the X direction positive side. A pitch shaft 333a that is parallel to the Y direction is inserted in this bearing 332a, and a pitch shaft 333b that is parallel to the Y direction (discussed below) is mated to the rotation stop 332b, which allows the pitch movement frame 332 to slide in the first direction (Y direction).
A yaw movement frame 334 that moves the image blur correcting lens group L3 in the second direction (X direction) is attached to the pitch movement frame 332 on the Z direction negative side. The yaw movement frame 334 is provided with a fixing component 334a that fixes both ends of the pitch shaft 333a to slide the above-mentioned pitch movement frame 332 in the pitch direction (Y direction), and the pitch shaft 333b, which is mated to the rotation stop 332b on the X direction positive side. The yaw movement frame 334 has a bearing 334b on the Y direction positive side, and a fixing component 334c to which a yaw shaft 335b and the two ends thereof are press-fitted and fixed on the Y direction negative side. A yaw shaft 335a that is parallel to the X direction is inserted into this bearing 334b, and the yaw shaft 335b that is parallel to the X direction is mated to a rotation stop 308d of a three-group frame 308, which allows the yaw movement frame 334 to slide in the second direction (X direction).
The three-group frame 308 provided on the Z direction negative side with respect to the yaw movement frame 334 is provided with a fixing component 308c that fixes both ends of the yaw shaft 335a for sliding the above-mentioned yaw movement frame 334 in the yaw direction (X direction), and the rotation stop 308d to which the yaw shaft 335b is mated.
A rectangular electrical substrate 336 is attached to the face of the pitch movement frame 332 on the Z direction negative side. The electrical substrate 336 is provided with a first coil 337y that drives the image blur correcting lens group L3 in the pitch direction and a second coil 337x that drives the image blur correcting lens group L3 in the yaw direction, and a hole element 338y that detects the position of the image blur correcting lens group L3 in the pitch direction and a hole element 338x that detects the position of the image blur correcting lens group L3 in the yaw direction. The coils 337y and 337x are constituted integrally with the electrical substrate 336 as laminated coils.
Magnets 339y and 339x are dipole magnetized on one side. These magnets 339y and 339x are respectively fixed to yokes 340y and 340x that are substantially U-shaped in cross section. The yoke 340y is press-fitted to a mating component 308y of the three-group frame 308 from the Y direction. Similarly, the second yoke 340x is press-fitted to a mating component 308x of the three-group frame 308 from the X direction.
A first electromagnetic actuator 341y is constituted by the first coil 337y, the first magnet 339y, and the first yoke 340y. Similarly, a second electromagnetic actuator 341x is constituted by the second coil 337x, the second magnet 339x, and the second yoke 340x. The first electromagnetic actuator 341y drives the pitch movement frame 332 in the pitch direction (Y direction), which is the first direction, and the second electromagnetic actuator 341x drives the pitch movement frame 332 in the yaw direction (X direction), which is the second direction.
With the constitution described above, when current flows to the first coil 337y of the electrical substrate 336, the first magnet 339y and the first yoke 340y generate electromagnetic force in the pitch direction (Y direction), which is the first direction. Similarly, when current flows to the second coil 337x of the electrical substrate 336, the second magnet 339x and the second yoke 340x generate electromagnetic force in the yaw direction (X direction), which is the second direction. Thus, the image blur correcting lens group L3 is driven by the two electromagnetic actuators 341y and 341x in the Y and X directions, substantially perpendicular to the optical axis of the Z direction.
Next, position detectors 342y and 342x that detect the position of the image blur correcting lens group L3 will be described. The hole elements 338y and 338x, which convert a magnetic flux into an electrical signal, are positioned and fixed to the electrical substrate 336. The magnets 339y and 339x of the electromagnetic actuators 341y and 341x described above also serve as detection magnets. Therefore, the position detectors 342y and 342x are constituted by the hole elements 338y and 338x and the magnets 339y and 339x. Here, the state of the magnetic flux of the magnets 339y and 339x will be described through reference to FIG. 22. The horizontal axis in the graph shows the position in the pitch direction (Y direction) or yaw direction (X direction) around the optical axis, and the vertical axis shows the magnetic flux density. The middle of the horizontal axis is the boundary portion of dipole magnetization of the magnets 339y and 339x, at which point the magnetic flux density is zero. This position substantially coincides with the optical axis center of the image blur correcting lens group L3. When the hole elements 338y and 338x are moved with respect to the magnets 339y and 339x, within the range indicated by the dotted lines, the center of which is the position at which the displacement is zero, the magnetic flux density varies substantially linearly with respect to changes in the amount of displacement. Therefore, it is possible to detect the position of the image blur correcting lens group L3 in the pitch direction (Y direction) or the yaw direction (X direction) by detecting the electrical signal outputted from the hole elements 338y and 338x. 
A flexible printed cable 343 is attached to the electrical substrate 336 and transmits signals between the coils 337x and 337y, the hole elements 338y and 338x, and the circuit of a camera main body (not shown).
An image blur correction apparatus 331 is constituted by the above-mentioned constituent elements 332 to 343.
Also, as shown in FIG. 23A, with the constitution disclosed in JP2000-32785, a pressurizing mechanism comprises a biasing member 403 that generates a biasing force, and a transmission member 402 that rotates around a rotational shaft 404 and transmits the biasing force generated by the biasing member 403 to a vibration actuator 401. The transmission member 402 converts the direction A of the biasing force generated by the biasing member 403 into a direction P.
Also, as shown in FIG. 23B, with the constitution disclosed in Japanese Laid-Open Patent Application JPH9-285153, a support member 508, consisting of a flat spring 507 to which a tapered pin 506 is attached, is disposed opposite a vibration actuator 501 equipped with an elastic body 502 and piezoelectric bodies 503 and 504. A relative motion member 509 comes into contact under pressure with the vibration actuator 501 and performs relative motion with the vibration actuator 501. The support member 508 is fixed to a fixing member 505 and the vibration actuator 501, the position of the vibration actuator 501 is restricted to the direction of relative motion, and at the same time, the vibration actuator 501 is supported displaceably in a direction substantially parallel to the direction of pressurization of the relative motion member 509.